Patent Literature 1 discloses an example of a pipe holding connection structure. In the pipe holding connection structure, a first pipe is held and the first pipe and a second pipe are connected to each other in a portion in which a pipe passes through an opening in a vacuum container, wherein through the pipe a fluid flows. This will be described with reference to FIG. 1.
A housing 8 is fixed to an outer wall in a vacuum container 4 with an opening 6 using bolts 10 to air-tightly close the opening 6. An O ring 12 configured to vacuum-seal between the housing 8 and the vacuum container 4 is provided between the housing 8 and the vacuum container 4.
A portion near an end portion of a first pipe 16 passes through the opening 6 in the vacuum container 4 and the housing 8, wherein the first pipe 16 is provided inside the vacuum container 4 and through the first pipe 16 a fluid 2 flows. O rings 14 configured to vacuum-seal between the housing 8 and the first pipe 16 are provided between the housing 8 and the first pipe 16. The fluid 2 may be, for example, a cooling medium such as cooling water or various gases used to cool the first pipe 16.
An end portion of the first pipe 16 is inserted into an end portion of a second pipe 18, wherein the second pipe 18 is provided outside the vacuum container 4 and through the second pipe 18 the fluid 2 flows. The two pipes 16 and 18 are connected to each other, and the connection thereof is sealed by an O ring 28. Outward movement of the first pipe 16 from the vacuum container 4 is stopped by a locking part 20.
A flange 22 is provided on an end portion of the second pipe 18, at least two stud bolts 24 are provided between the flange 22 and screw holes 9 in the housing 8, and the pipe 18 is fixed to the housing 8 by the stud bolts 24. Reference numeral 26 is a nut.
The first pipe 16 is held with respect to the vacuum container 4 using the above-described structure and thus the pipe 16 and the pipe 18 can be connected. Therefore, the fluid 2 can be supplied from the pipe 18 to the pipe 16 or from the pipe 16 to the pipe 18.